Page 102 - PG 101-Course notes مذكرة النظري 24-25 with spec

Medicinal plants (PG 101) Level 1 Clinical Pharmacy-PharmD

2- The cambium produces secondary xylem to the inside and secondary phloem to the

outside. These rings of xylem and phloem are traversed by MRs (medullary rays).

3- Periderm usually arises in the subepidermal cortex. Parenchyma cells become

meristematic and form a Cork Cambium or Phellogen .This produces Cork Cells or

Phellem to the outside .

N.B. periderm consists of three parts: phellogen (cork cambium), the phellem

(cork) and the phelloderm (secondary cortex).

● (Suberin (a wax) Is secreted into the walls of the Cork Cells. This makes them
(
.
waterproof and pathogen-proof

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